According to three people with direct knowledge of the news who were not authorized to speak about it, Lady Gaga has fired her manager, Troy Carter, just days before the release of her new album. Mr. Carter had managed Lady Gaga - whose real name is Stefani Germanotta - since 2007, before the release of her first album, and he is regarded in the music industry as an important force in her rise to megastar status.The last, "Born This Way," in 2011, had an enormous and flawlessly executed marketing campaign, and sold more than 2 million copies in the United States.